Comparing with a traditional cathode ray tube (CRT), a liquid crystal display (LCD) has advantages of smaller size, lighter weight and low radiation ever since it was invented, and thus is popular. A schematic side view illustrating the major frame of a conventional LCD is shown in FIG. 1.
Referring to FIG. 1, the conventional LCD mainly comprises the following elements: an upper side polarizer 1, a color filter 2, an alignment layer 3, a spacer 4, a liquid crystal 5, a thin film transistor (TFT) array substrate 6, a lower side polarizer 7, a conductive paste 8, a frame sealant 9 and a TFT. The light necessary for the LCD to display images can enter into the LCD from a light guiding plate 11 below the lower side polarizer 7. An optical film (i.e. a light diffusion plate) 12 is between the lower side polarizer 7 and the light guiding plate 11, and a white sheet 13 is below the light guiding plate 11. A cold cathode fluorescent lamp (CCFL) is usually used in the conventional LCD as a light source 14 which is covered with a lamp holder 15. Since the light emitted by the CCFL is a white light intermingled with lights of various wavelengths, the color filter 2 is used to filter the emitted light when the light emitted by the CCFL enters into the LCD, such that the LCD can provide the function of color display.
In order to illustrate in detail how the LCD accomplishes color display, please refer to FIG. 1 again. The color filter 2 is composed by a plurality of red light filtering layers 2a through which merely a red light band is allowed to pass, a plurality of green light filtering layers 2b through which merely a green light band is allowed to pass and a plurality of blue light filtering layers 2c through which merely a blue light band is allowed to pass, wherein the red light filtering layers 2a, the green light filtering layers 2b and the blue light filtering layers 2c are arranged in turn, adjacent to one another, on the surface of the color filter 2, that is, the sequence thereof is a red light filtering layer 2a, a green light filtering layer 2b, a blue light filtering layer 2c, 2a, 2b, 2c, . . . . 
After the light entering into the LCD is treated by the color filter 2, a red light, a green light and a blue light which go through any three sequentially arranged red light filtering layer 2a, green light filtering layer 2b, blue light filtering layer 2c on the color filter 2, respectively enter onto three pixels sequentially arranged on the LCD such that the three pixels display a red dot, a green dot and a blue dot respectively. Because the intensity of the dots on the aforesaid pixels can be controlled by the LCD, any three sequentially arranged pixels on the LCD are allowed by the conventional LCD via the above-mentioned principle to respectively display red dots, green dots and blue dots of different brightness, and to be formed as one display unit. Thus, each display unit can provide an effect of a color display in terms of a human's eyes. Therefore, the LCD having a plurality of display units may fulfill the function of displaying color pictures.
In manufacture of the above-mentioned LCD, a color filter is an indispensable element and accounts for a great proportion in material costs. Since the fabricating cost of the color filter is high, the manufacturing cost of the LCD cannot be greatly reduced. Furthermore, The resolution is restricted due to the fact that one display unit of the conventional LCD is composed by three sequentially arranged pixels. Hence, to resolve the above-mentioned problems is the goal of the manufacturers.